Estimation on the real number of novel influenza A (H1N1) cases, Beijing, 2009

VernacularTitle:北京市2009年甲型H1N1流感实际感染人数的估算
Author: Xiao-Li WANG ¹ ; Peng YANG ; Xiang-Feng DOU ; Yi ZHANG ; Wen-Ting LIU ; Ying DENG ; Xing-Huo PANG ; Xiong HE ; Quan-Yi WANG
Author Information

1. 北京市疾病预防控制中心
Keywords: InfluenzaA (H1N1); Infection; Estimation; Monte Carlo approach
From: Chinese Journal of Epidemiology 2010;31(5):497-499
CountryChina
Language:Chinese
Abstract: Objective To estimate the real number of novel influenza A(H1N1 ) infection in Beijing, 2009. Methods A multiplier model (Impact 2009 v 1.0 software) based on Monte Carlo approach was used to estimate the real number of novel influenza A (H1N1 ) based on the number of influenza-like illness (ILI) cases, novel influenza A(H1N1 ) positive rate among ILI cases and rate on clinical visit of ILIs in secondary and tertiary hospitals. Results There were 1.80 million (90%CI: 1.46-2.30) estimated novel influenza A (H1N1) cases in 2009 in Beijing with the rate of infection as 11.0%. One reported case would represent 167 real infections. The highest age groups of infection were 0-4 years and 5-14 years, being 32.5% and 33.3%, respectively. Conclusion Laboratory-confirmed infections with novel influenza A (H1N1 ) only represented a fraction of the total cases in a population, suggesting that it was imperative to estimate the real number of novel influenza A (H1N1) infection.